SPID#: 53 A major focus of our research is the ontogeny of macaque screams. These are acoustically distinct calls that elicit support from allies during agonistic encounters and encode specific information about an opponent (such as its relative dominance rank and, in the case of rhesus macaques, its relatedness to the caller) as well as the intensity of the attack. In order for a monkey to use a contextually correct call, it must have knowledge of the network of kinship and dominance relationships within its group. The same is true for an ally hearing the call. Consistent with these requirements, we found gradual attainment of proficiency characterizes both scream usage and production. Individual vocal recognition of callers is critical to this system of agonistic recruitment. Vocalizations are likely to have multiple referents and our analyses of pigtail macaque screams revealed evidence of vocal signatures that characterize and, perhaps, serve to identify, matrilineal kin groups. Thus, in addition to the information screams provide about features of the external agonistic context, these calls can also convey information about kinship. Matrilineal kinship is often a major factor underlying primate agonistic alliance formation and our evidence points to such a recognition system in the recruitment screams of pigtail macaques. Ongoing work involves study of the screams of foster-reared and natural infants in an attempt to establish the developmental origins of these vocal signatures.